This invention relates to the field of electronic apparatus assembly and specifically to an arrangement for mounting a printed circuit board to a chassis, then using the chassis as a board carrier during the waveline soldering process.
Increased automation of production lines has been a continuing goal in the electronics industry for some years. New impetus was added as components were miniaturized and new soldering methods were developed to eliminate hand soldering of each small component. It is known in the art to insert component leads into holes in an insulating board having most or all of its interconnections plated or printed on the board. The board is then fastened to a carrier or pallet which carries the board through the fluxing, soldering and cleaning steps on the production line. After these steps, the pallet is removed, the chassis fastened to the board and other components added and hand soldered. The use of pallets is costly for several reasons: relatively high original cost coupled with relatively short life, and the time and cost of labor required to attach, remove, clean, then move the pallets back to the point of attachment. Pallets continued to be used, however, since any known method of attaching the chassis to the printed circuit board before the soldering process would cause the board to warp due to the heat and stress. This warping frequently caused failures in the apparatus during testing or in use, due to minute cracks in the printed leads or loosened connections.